The rescue of the Salyut 7 space station | Hacker News Reader

The rescue of the Salyut 7 space station

astronomy.com

104 pointsyakkomajuri36 comments

Reminds me of how you come to your dacha in -30C at the height of winter to prepare it for New Year party.

> The rescue of Salyut 7 has sometimes been compared to the ill-fated flight of Apollo 13: both missions involved dead and freezing spacecraft that put human lives at risk,

This risk was voluntary - since the power failures happened when nobody was occupying the station, the mission planners could have just let the station die. Apollo 13 (Or the fire on Mir) was not - as human lives were imminently at risk, until the problems could be repaired.

Absolutely incredible work went into rescuing the craft in both situations. I can't imagine what it would be like to try to manually dock with an unresponsive, free-spinning space station.

Such risks would likely not be allowed today.

If it happened today, do you hire a pilot to try it, or a gamer? heh.

This was a more detailed story on the recovery: https://arstechnica.com/science/2014/09/the-little-known-sov...

Lots more details, including transcripts of some of the procedures, such as the opening of the hatch.

The 2017 movie with the same name is also worth a watch.

I loved it. It's spectacular, over the top dramatic, and so quintessentially Russian. Just don't treat it as a documentary -- it combines anomalies from several missions into one and then throws in several mroe invented (implausible) space mishaps for good measure.

I watched it around the time it came out, and to this day I remember how remarkable it was to see a Russian screenplay produced in the Hollywood space blockbuster style. It's one of the more interesting space films out there, even if indeed it was overly dramatic and had many overused movie tropes.

Hehe, yeah, there are some details that are just so culturally russian... like alcohol on the station :)

couldnt be more fantastical than the car themed space adventure that Fast & Furious 9 was

another very very good Russian-Hollywoodian style film is 'The Age of Pioneers' about the absolute madness of the Voskhod 2 (first spacewalk...they were mad as hell)

of a different kind but still beautiful is 'Out of the Present', which shows the daily activities filmed by the single cosmonaut who remained on board the mir during the fall of the urss.

Totally loved it; under-acclaimed and worth a watch.

It's an excellent movie

If the power was out, how did ground engineers know what the temperature inside the station was? My guess is that they could calculate absorbed and emitted energy and figure it out that way, but I'd be curious to know for sure.

My guess would be that it was measured after the docking, but before they began to reactivate the station.

It always surprises me that we let these space stations decay out of orbit instead of glomming them on to something else. I guess the extra delta vee cost of putting new things in orbit is negligible...

Rendezvousing with another orbiting object requires a Hohmann[1] or bi-elliptic[2] transfer maneuver in order to "catch up" to the target object. This requires multiple engine burns, and thus lots of delta-v.

If the two objects are in different orbital inclinations, an orbital inclination change[3] maneuver is also required. This requires very long, possibly multiple engine burns, and thus lots of delta-v.

In short, "glomming" a station onto another requires quite literally astronomical amounts of delta-v. It's not that launching new stations into orbit is cheap, it's that moving objects in orbit is astronomically expensive as to be downright impractical or even impossible.

[1]: https://en.wikipedia.org/wiki/Hohmann_transfer_orbit

[2]: https://en.wikipedia.org/wiki/Bi-elliptic_transfer

[3]: https://en.wikipedia.org/wiki/Orbital_inclination_change

You are perhaps exaggerating the "astronomical" delta-V required. Space stations are generally in a low ~400km prograde circular orbit, at an inclination efficient for an northern hemisphere launch.

For example, you could push the last stable Mir into the orbit of the ISS using only a few hundred m/s delta-v, regardless if it was a good idea or not. Of course, you could construct other scenarios where docking is not possible with current available thrust options.

Delta-v is a change in velocity, so "only a few hundred m/s of delta-v" isn't painting the entire picture. The more massive an object is, the more energy (aka fuel) it takes to impart a given amount of velocity change (aka delta-v) upon it.

Both a small satellite and a big station module need the same "only a few hundred m/s of delta-v", but the amount of fuel needed to accomplish that maneuver will be astronomically different between them because the station module is so much more massive.

You can move the goalposts, but still aren't getting to "astronomical" energy, just linear with the mass. If a Dragon or Soyuz craft has fuel for 400m/s in orbit maneuvering, that's about 40m/s for a 10x more massive structure. So definitely plausible, could even happen over a large number of crew rotations.

Both crafts are automated so you could hypothetically use the payload mass and volume to deliver extra fuel tanks, with plumbing to the onboard engines. So a full orbit change could happen in a few such flights.

Hopefully as ion engines and such catch on for these exact sorts of maneuvers we'll see more efforts to glom stations together rather than plunge them back to Earth.

At some point, you are better off launching a new station than trying to maintain an old one. They constantly need repairs for things that break and it gets worse over time. They're not gleaming perfection like the Enterprise, it's more like trying to maintain a creaky thirty-year-old RV.

> They're not gleaming perfection like the Enterprise, it's more like trying to maintain a creaky thirty-year-old RV.

The ISS has a mould problem due to spores brought in by crew rotations. The crews have to spend significant amounts of time each day just cleaning walls and other surfaces.

https://www.cbc.ca/news/science/international-space-station-...

I had high hopes that the Mir fungus would be mutated by space radiation and then survive re-entry. Awesome basis for a sci-fi/horror film.

Not exactly the same concept, but Life (2017) [1] comes close.

[1] https://letterboxd.com/film/life-2017/

We always decommission boats, planes, buildings, and space stations are no different. They are even more prone to issues, external or internal, are very difficult to repair or upgrade.

They are at low orbits which would need constant servicing to stay there, and they big and heavy, so moving them up into a higher permanent orbit would be very expensive.

also it reduces space junk to let them decay out.

I agree with purpleflame's sentiment though. Clearly they'd just boost it to a higher orbit if the fuel mass they need to lift for that is smaller than the mass they expect to later salvage from it, so apparently it's not worth it, but it's rather surprising and seems like a waste even if it's, economically, not

It's also worth mentioning that materials wear out in space in ways we don't always appreciate and certainly did not in the golden era of the Soviet space stations. The Mir, an upgrade over the Salyut program, was pretty trashed by the time it was abandoned. It's absolutely not worth boosting dangerous trash for it to potentially break up.

That said, it is sort of a shame we didn't capture Salyut 7 and bring it back down safely, or at least a chunk of it. It would have been interesting to see what uncontrolled heating and cooling does to a body meant for human habitation that big in low orbit.

Would have required using the space shuttle to retrieve a Soviet space station. Impossible, but a very fun idea :)

Would the shuttle have landed in the USSR or would Salyut have arrived in the USA?

The Buran had about the same payload capacity as the Space Shuttle (slightly more even). It's first (and only) orbital test flight was in '88, 2.5 years before the Salyut deorbit. Had the Soviet Union been just a smidge more solvent and politically stable we might have the whole Salyut 7 sitting in a museum somewhere. All it would have taken was a slightly accelerated Buran program, a Soviet Union that survived maybe 3 years longer, and a decision that bringing back a decommissioned station is a great test mission that boosts national pride. A near miss in history.

https://en.wikipedia.org/wiki/Buran_(spacecraft)

Hah! Fun question. While I think if you ripped the solar panels and other instrumentation off you could _just_ fit the Salyut in the Shuttle payload bay it was too heavy for a safe return trip. But, I think the Salyut's orbit would have required a USSR launch? Unless alternate history humanity made a truly humongous specialty retrieval craft and inclination changes meant nothing to it. :)

> "With the station back up and running, the crew of Soyuz T-13 was no longer on a rescue mission. It was time for them to settle in. Dzhanibekov remained in orbit for 110 days, while Savinykh spent 168 days on the station (they returned home aboard different, subsequently launched, Soyuz flights)."

How could they both return home on different Soyuz flights? In other words, what happened to the Soyuz they arrived in?

Soyuz can fit 3 but can be flown with less (modern Soyuz can be unmanned). They arrived on Soyuz T-13; later, T-14 arrived with a relief crew of 3; T-15 came with 2. So that's 7 cosmonauts lofted with 9 seats.

(T-15 actually docked with both Salut 7 and Mir, the first spacecraft to ever dock with two different stations on the same mission.)

Be interesting, thanks.

Sorry I meant, very interesting of course.

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